Amolecule that can be used as a molecular clock has a neutral mutation rate of one mutation per 5 million years. how many years ago did two species share a common ancestor if the molecules found in these two species differ by a total of eight mutations? 1.5 million years 10 million years 40 million years 20 million years branliest answer and 5.0 rate just me

20 million years

Explanation:

If we have a neutral mutation rate of one mutation per 5 million years, then the total of eight mutation between the two different species would be 20 million years. This is because both species will have 4 mutations in those 20 million years, so combined, both by 4, will have 8 mutations between them. So few mutations on so much time will result in two species that are very similar to each other even after 20 million years of evolution, even making them hardly distinguishable, especially if it comes to defining fossil records from them both. A nice example of this are the members of the felidae (cat) family, which are all very closely related, and are almost identical, thus making it extremely hard to distinguish two species of the same or similar size by their fossils.